There is a known image-capturing element that converts an optically formed optical image into an electrical signal. The image-capturing element includes pixels that output signals for focus detection (for example, refer to PTL 1).
In order to provide some pixels of the image-capturing element with a distance-measuring function that utilizes a pupil phase-difference method (hereafter, referred to as phase-difference detection pixels), light-receiving surfaces of the phase-difference detection pixels are partially shielded from light.
Although it would be desirable to arrange the phase-difference detection pixels over the entire surface of the image-capturing element so as to allow the distance to a subject to be correctly measured at every frequency, the image quality would be degraded due to reduction of the number of pixels that form an image when the number of phase-difference detection pixels is increased. In order to prevent such degradation of image quality, a method has been proposed in which phase-difference detection pixels are arranged in a distributed manner.
When phase-difference detection pixels are arranged so as to be concentrated in only pixels having a specific spectral sensitivity in the case where the phase-difference detection pixels are arranged with high density in a so-called Bayer array image-capturing element, for example, degradation of the information of this spectral sensitivity is significant, and therefore, phase-difference detection pixels are instead arranged in a distributed manner across pixels having different spectral sensitivities.
Since the phase-difference detection pixels are partially shielded from light as described above, the outputs of the phase-difference detection pixels cannot be used as pixel data without being altered, and therefore a method has been proposed in which the outputs are corrected using the output values of the surrounding pixels (for example, refer to PTL 2). In the correction method disclosed in PTL 2, for example, the output value of a phase-difference detection pixel is accurately corrected by determining the edge patterns and the like of surrounding pixels in the region surrounding the phase-difference detection pixel, and adjusting the use ratio between the output value of the phase-difference detection pixel and the output values of the surrounding pixels in accordance with the extent of the edge patterns.